title: Age-related autophagy alterations in the brain of senescence accelerated mouse prone 8 (SAMP8) mice.
abstract: Autophagy is responsible for the degradation of long-lived proteins and damaged organelles intracellular, even extracellular,and autophagy is proved to have relationship with Alzheimer's disease (AD) and aging. The senescence accelerated mouse prone 8 (SAMP8) was a non-genetically modified mice widely used as a rodent model of aging and senile dementia. However, little was known about the age-related changes of autophagy in the brain of SAMP8 mice. To better understand the precise relationship between aging, autophagy and neurodegeneration, we explored the time course of cognitive ability, ubiquitin-positive inclusions, ultrastructure of neurons and detected the expression of LC3 and Beclin 1 protein in different brain regions of 2, 7 and 12-month-old SAMP8 and SAMR1 mice. We found that 7 and 12-month-old SAMP8 mice presented cognitive decline and ubiquitinated proteins enhanced. In the hippocampal neurons of 12-month-old SAMP8 mice, lots of dense clumps and autophagic vacuoles were found in the cytoplasm and axons. The LC3-II expression showed an increase in hippocampus and cortex of 7 and 12-month-old SAMP8 mice. The expression of Beclin 1 displayed a significant increase in 7 months old and a decline in 12 months old mice. Based on these data, we suggest that the autophagic activity maybe increase reactively at the beginning of AD and then showed a decline with aging, and the pathological changes of 12-month-old SAMP8 mice are more similar to the late-onset AD in the perspective of autophagy.
authors.affiliation: Department of Neurology, Frist Hospital of Hebei Medical University, Shijiazhuang 050031, Hebei, PR China.
authors.forename: Qinying
authors.initials: Q
authors.lastname: Ma
authors.forename: Jing
authors.initials: J
authors.lastname: Qiang
authors.forename: Ping
authors.initials: P
authors.lastname: Gu
authors.forename: Yanyong
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Geng
authors.forename: Mingwei
authors.initials: M
authors.lastname: Wang
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy; D000071186:Beclin-1; D002540:Cerebral Cortex / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D002479:Inclusion Bodies / Q000378:metabolism; D008297:Male; D018782:Maze Learning; D008568:Memory / Q000502:physiology*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000648:ultrastructure; D025801:Ubiquitin / Q000378:metabolism; D057149:Ubiquitinated Proteins / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; C115010:Becn1 protein, mouse; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D025801:Ubiquitin; D057149:Ubiquitinated Proteins